Connecting pole for a rechargeable battery, rechargeable battery housing and machine for producing a connecting pole

ABSTRACT

The invention relates to a connecting pole ( 1 ) for a rechargeable battery ( 12 ) having the following features: a) the connecting pole ( 1 ) has a connecting section ( 2 ), in which a pole terminal can be fastened on the connecting pole ( 1 ), b) the connecting pole ( 1 ) has a fastening section ( 3 ), in which the connecting pole ( 1 ) can be fastened in a housing part ( 5 ) of the rechargeable battery ( 12 ), c) the fastening section ( 3 ) has a labyrinth section ( 4 ), d) the outer wall ( 6 ) of the connecting pole ( 1 ) has, in the labyrinth section ( 4 ), one or more peripheral projections ( 7, 8, 10 ), e) at least two adjacently arranged peripheral projections ( 70, 71, 72, 73, 80, 81, 82, 83 ) are flanged in pairs in the mutually facing direction, wherein a recess ( 11 ) is formed on each of the peripheral projections ( 70, 71, 72, 73, 80, 81, 82, 83 ) with respect to the outer wall ( 6 ) of the connecting pole ( 1 ) by the flanged region. The invention also relates to a rechargeable battery housing or a part thereof with at least one such connecting pole and to a machine for producing such a connecting pole.

The invention relates to a connecting pole for a rechargeable battery inaccordance with the preamble of claim 1. The invention further relatesto a rechargeable battery housing or a section thereof having at leastone such connecting pole in accordance with claim 6 as well as a machinefor manufacturing such a connecting pole in accordance with claim 7.

Connecting poles for rechargeable batteries serve to establish anelectrical contact between the rechargeable battery and electricaldevices which the rechargeable battery is to supply with power. In thecase of a starter battery for a motor vehicle, the corresponding poleterminals are screwed to two connecting poles of the starter battery.

A connecting pole for a rechargeable battery is known from DE 42 41 393C2. The connecting pole described therein comprises a base part havingperipheral grooves which can be inserted into a housing of therechargeable battery. The peripheral grooves form a labyrinth seal witha plastic material which fills the grooves.

The invention is based on the objective of specifying a connecting polesuitable for forming a labyrinth seal with a plastic material which isof simpler and more economical manufacture.

This objective is accomplished by the invention as specified in claims1, 6 and 7. Advantageous embodiments of the invention are set forth inthe subclaims.

Claim 1 proposes a connecting pole for a rechargeable battery having thefollowing features:

-   a) the connecting pole comprises a connecting section in which a    pole terminal can be attached to the connecting pole,-   b) the connecting pole comprises an attachment section in which the    connecting pole can be attached in a section of the rechargeable    battery housing,-   c) the attachment section comprises a labyrinth section,-   d) the outer wall of the connecting pole exhibits one or more    peripheral projections in the labyrinth section,-   e) at least two adjacently arranged peripheral projections are    flanged in pairs in the mutually facing direction, wherein the    flanged region forms an undercut on each peripheral projection in    relation to the outer wall of the connecting pole.

The term “section” herein refers to sections in the longitudinaldirection of the connecting pole; i.e. in the direction of thelongitudinal axis L depicted in FIG. 1.

The invention has the advantage of specifying a connecting pole with alabyrinth section having peripheral projections which can bemanufactured in simpler and thereby more economical manufacturing steps.While it is necessary to produce the projections with a hook-likeprofile in the connecting pole cited at the outset, e.g. by cylindricalor flat die rolling of the corresponding section of the connecting pole,such laborious measures are able to be dispensed with in the case of theinventive connecting pole. This allows simpler and more economical toolsto be used, particularly a flanging tool for the paired flanging of twoadjacently arranged peripheral projections toward each another. Becausetwo peripheral projections are in each case flanged in pairs toward oneanother, the flanging tool works substantially in the absence of thrustload since the respective flanging forces essentially cancel each otherout. In addition, compared to the known manufacturing methods, time isalso saved when manufacturing the connecting pole. All of this leads tolower manufacturing costs. Undercuts can hereby be easily produced onthe outer wall of the connecting pole which form an optimal barrieragainst acid seeping from the rechargeable battery after the connectingpole is embedded in the injection molding material of the rechargeablebattery housing.

The flanged region of the peripheral projections can be flanged inuniform or non-uniform, i.e. sinuous, manner. Particularly advantageousis for a uniform flanged region of the peripheral projection to form acontinuous ring around the outer wall of the connecting pole.

The invention can be advantageously realized both in a connecting polefor a passenger car battery as well as in a connecting pole for acommercial vehicle battery (for commercial vehicles).

The peripheral projection(s) in the labyrinth section can in principlebe realized with different profiles. An annular form is cited as thebasic form for the peripheral projection. One or more of the peripheralprojections can also exhibit a hook-shaped profile.

According to one advantageous further development, the flanging onlyproduces one single undercut per peripheral projection; i.e. anasymmetrical profile to the peripheral projection results. This isparticularly advantageous to the manufacture.

Advantageous for the economical manufacture of the connecting pole is tofirst produce the peripheral projection without undercuts. According toone advantageous further development of the invention, it is thereforeprovided for the at least two adjacently arranged peripheral projectionsto otherwise be free of undercuts; i.e. aside from the flanged region.This allows simple and quick manufacture of the connecting pole from ane.g. cylindrical or tubular connecting pole blank, in which theperipheral projections are worked in first without undercuts in anextrusion press step. The connecting pole can also be manufactured withperipheral projections initially free of undercuts in a molding process.At least two adjacently arranged peripheral projections can thereafterbe flanged in pairs in the mutually facing direction in a flanging step,whereby a respective undercut is then formed.

According to one advantageous further development of the invention, oneor two further peripheral projections are arranged in the labyrinthsection. Providing the one or two further peripheral projections has theadvantage of improving the labyrinth's sealing action. It has been shownthat too many peripheral projections does not lead to furtherimprovement but only increases the manufacturing costs and reduces thestability of the peripheral projections. In a connecting pole ofconventional design, it is advantageous for the distance between twoadjacent peripheral projections to be in the range of 0.8 to 2 mm,whereby a value of approximately 1.5 mm has proven optimum. To ensuresecure and stable embedding of the connecting pole in the material ofthe housing section, the spacings should not be too large. Spacings tooclose together diminish the extent to which the grooves formed betweenthe peripheral projections can be filled within the injection moldingmaterial of the housing section, particularly when polypropylene (PP) isused as the material. Peripheral projections spaced too close togetherare hereby disadvantageous for the influent action of the injectionmolding material into the grooves.

According to one advantageous further development of the invention, theconnecting pole comprises a peripheral projection having a system ofteeth on the outer periphery in the attachment section between theconnecting section and the labyrinth section. The tooth system canadvantageously realize an anti-rotation means to prevent unwantedrotating of the connecting pole in the material of the rechargeablebattery housing. In one advantageous further development of theinvention, the tooth system has teeth numbering from 6 to 9. It hasparticularly been shown that 8 teeth is particularly advantageous andyields a good compromise between the mechanical stability of theconnecting pole teeth and the stability of the connecting pole in theplastic material of the rechargeable battery housing. Too many teethinevitably leads to reduced dimensions of each individual tooth, wherebythe stability of the individual teeth decreases. Too few teeth leads toa decrease in anti-rotation effectiveness since the stability of theconnecting pole in the plastic material of the rechargeable batteryhousing is reduced.

The invention further relates to a rechargeable battery housing or asection thereof comprising at least one connecting pole of theabove-described type, wherein the at least one connecting pole withattachment section is embedded in a rechargeable battery housing sectionby injection molding.

The invention further relates to a machine for manufacturing aconnecting pole of the above-described type. The machine is therebydesigned to integrally form on a blank a labyrinth section having one ormore peripheral projections in the attachment section on the outer wallof the connecting pole by means of at least one extrusion press step.Such an extrusion press step can be realized with simple tools and athigher processing speeds than the rolling step cited at the outset.

The cited blank can be of e.g. cylindrical, truncated conical or tubularshape; i.e. already having an inner cavity. Should the blank not yethave an inner cavity, such as the case for example with a solid cylinderor truncated cone, the machine is advantageously designed to first forma small central cavity in the blank in a first extrusion press step,e.g. with a thin borer tool. The machine is further designed to enlargethe small cavity just produced with a larger borer tool in a secondextrusion press step, which hereby concurrently serves centeringpurposes. The integral forming of the peripheral projections can thenensue at the same time during the second extrusion press step.

According to one advantageous further development of the invention, themachine is designed to flange at least two adjacently arrangedperipheral projections in pairs in the mutually facing direction in asubsequent flanging step.

The connecting pole can alternatively also be manufactured in a moldingprocess. In this case, the machine is designed to form a connecting polehaving a labyrinth section with one or more peripheral projections onthe outer wall of the connecting pole in a molding process.

The following will reference drawings based on embodiments in describingthe invention in greater detail.

Shown are

FIG. 1 is a sectional view of a connecting pole in the longitudinaldirection,

FIG. 2 is a sectional view of a further embodiment of a connecting polein the longitudinal direction,

FIG. 3a ) is a top plan view of embodiments of the connecting poleaccording to FIGS. 1-2,

FIG. 3b ) is an additional top plan view of embodiments of theconnecting pole according to FIGS. 1-2,

FIG. 3c ) is an additional top plan view of embodiments of theconnecting pole according to FIGS. 1-2, and

FIG. 4 a sectional view of a rechargeable battery comprising aconnecting pole.

In the figures, the same reference numerals are used for elements whichcorrespond to one another.

FIGS. 1 and 2 show respective embodiments of the connecting pole 1, inwhich the right side of same are depicted with still unflangedperipheral projections; i.e. in the connecting pole's state followingmolding or extrusion pressing. The same connecting pole 1 is depictedsubsequent the flanging process on the respective left side of FIGS. 1and 2; i.e. with peripheral projections respectively flanged in pairs.

FIG. 1 shows a connecting pole 1 in a longitudinal sectional view. Theconnecting pole 1 comprises a connecting section 2, an attachmentsection 3 and a labyrinth section 4. The connecting pole 1 has an outerwall 18 and an upper terminal surface 16 on its exterior in connectingsection 2. A peripheral projection 14 which can be of e.g. annular shapeis arranged on the exterior of the connecting pole 1 in attachmentsection 3 adjacent connecting section 2. The peripheral projection 14can also exhibit the system of teeth still to be described in greaterdetail below on its outer periphery. An outer wall 6 on the exterior ofconnecting pole 1 arranged in labyrinth section 4 adjoins the peripheralprojection 14. The outer wall 6 is interrupted by peripheral projections70, 71, 72, 73. Aside from the system of teeth, the connecting pole 1can be designed for example as a substantially rotationally symmetriccomponent.

As can be seen in FIG. 1, in the intermediate state depicted on theright during manufacture, in which none of the peripheral projections70, 71, 72, 73 have yet been flanged, the connecting pole 1 comprises apair of adjacently arranged peripheral projections 71, 72 ofasymmetrical profile which are already slightly oriented toward oneanother. These peripheral projections 71, 72 are then flanged in thenose area with a flanging tool, e.g. with a rolling tool guided aroundthe connecting pole 1, as is shown on the left of FIG. 1. It can berecognized here that the peripheral projections 71, 72 are to be flangedin succession, whereby undercuts are formed in regions 11. The injectionmolding material can collect in the undercuts 11 when the connectingpole is embedded in the material of the rechargeable battery housing,whereby particularly good sealing is obtained. On the left of theconnecting pole 1, FIG. 1 shows exemplary sections of a housing section5 of the rechargeable battery integrally formed on the connecting pole 1in an injection molding process. As is recognizable, the exterior of theconnecting pole 1 is embedded in the material of the housing section 5in attachment section 3. The peripheral projections 70, 71, 72, 73 forma labyrinth which provides for good sealing of the rechargeable batteryinterior relative to the environment.

The connecting pole 1 is of hollow inner design and comprises a cavity17. The inner cavity 17 serves for the introduction of a pole body, aswill be described below in conjunction with FIG. 4.

FIG. 2 shows a further embodiment of a connecting pole 1 in a comparableview to that of FIG. 1 which provides, in contrast to the embodiment ofFIG. 1, a first pair of peripheral projections 80, 81 and a second pairof peripheral projections 82, 83 underneath. The pairs 80, 81 and 82, 83respectively are in each case of comparable design to the peripheralprojections 71, 72 according to FIG. 1. As can be seen on the left inFIG. 2, a schematically depicted flanging tool 60, e.g. in the form of arolling tool, flanges the pairs 80, 81 and 82, 83 respectively ofperipheral projections are flanged to mutually face each other, wherebya total of four regions 11 with undercuts are produced.

In all the embodiments, the undercuts 11 of a pair of peripheralprojections 70, 71, 72, 73, 80, 81, 82, 83 produced by the flanging faceeach other; i.e. point toward each other.

FIG. 3a ), FIG. 3b ) and FIG. 3c ) show different embodiments of theconnecting pole 1 in top plan view, specifically from the terminalsurface 16 side. The upper terminal surface 16, outer side wall 18,inner cavity 17 as well as the peripheral projection 14 are recognizablein all three embodiments.

The peripheral projection 14 comprises an external system of teeth,illustrated by teeth 19, 20, 23. The teeth 19, 20, 23 prevent theconnecting pole from rotating in the plastic material of therechargeable battery housing. FIG. 3a ) hereby depicts one advantageousembodiment in which the six teeth 19 are in a uniformly distributedarrangement over the periphery of the connecting pole 1. FIG. 3b )depicts one advantageous embodiment with eight teeth 19 in a uniformlydistributed arrangement over the periphery of the connecting pole 1.

FIG. 3c ) insofar corresponds to the embodiment according to FIG. 3b ),whereby teeth 20, 23 having asymmetrical tooth flanks 21, 22 areprovided in FIG. 3c ) as an advantageous further development. Toothflank 21 thus has a smaller angle relative to the outer periphery ofperipheral projection 14 than tooth flank 22. Tooth 23 is of comparabledesign to tooth 20 with asymmetrical tooth flanks. Tooth 23 is herebyarranged mirror symmetrically to tooth 20. The tooth flanks 21 ofsmaller angle provide the opportunity to manufacture the connecting poleusing a split mold. The cheeks can thereby be readily separated from theconnecting pole upon its removal from the mold since there is noundercut in the direction of separation.

In a method for manufacturing a connecting pole, a labyrinth sectionhaving one or more peripheral projections is first formed on a blank inthe attachment section on the outer wall of the connecting pole by meansof at least one extrusion press step. In a subsequent flanging stepdirectly or indirectly following the extrusion press step, adjacentlyarranged peripheral projections are flanged toward one another in pairs.The flanging step can advantageously be realized with a peripheralrolling tool 60 rolled around the connecting pole 1. The connecting poleis thereby held in a fixing device. This allows the inventive connectingpole to be manufactured quickly and efficiently.

The cited blank can be of e.g. cylindrical, truncated conical or tubularshape; i.e. already having an inner cavity. Should the blank not yethave an inner cavity, such as the case for example with a solid cylinderor truncated cone, the method comprises at least two extrusion presssteps. In a first extrusion press step, a small central cavity in firstformed in the blank, for example with a thin borer tool. In a secondextrusion press step, the small cavity just produced is then enlargedwith a larger borer tool, which hereby concurrently serves centeringpurposes. The integral forming of the peripheral projections can thenensue at the same time during the second extrusion press step.

The connecting pole 1 can also be alternatively manufactured in amolding process.

FIG. 4 shows a section of a rechargeable battery 12 comprising thebattery case 13 and cover part 5 housing components. The cover part 5 isset on top of the battery case 13. Electrode plates forming a plate set40 are provided in the interior of the battery case 13. The plate set 40is electrically and mechanically connected to a pole body 42 by means ofa connector 41. As can be seen, the pole body 42 is introduced into theinner cavity 17 of the connection socket 1 and projects somewhat at theexterior of the rechargeable battery 12 from the connection socket 1embedded in cover part 5. The pole body 42 is dimensioned with asomewhat smaller diameter in this area than in the other areas. Anannular space is thereby formed between the pole body 42 and theconnection socket 1. This annular space serves in electrically andmechanically connecting the pole body 42 and the connection socket 1,e.g. by welding.

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 9. A connecting pole for arechargeable battery, the connecting pole comprising: a connectingsection, an attachment section, and a labyrinth section; an outer wallsurrounding a cavity arranged for introduction of a pole body, and aninner wall within the cavity, the entire inner wall having a smoothsurface; wherein a portion of the outer wall is interrupted a pluralityof peripheral projections, a peripheral projection from the plurality ofperipheral projections having an undercut flange.
 10. The connectingpole of claim 9, wherein the portion of the outer wall which isinterrupted by the plurality of peripheral projections is located on thelabyrinth section.
 11. The connecting pole of claim 9, wherein theplurality of peripheral projections comprises a pair of peripheralprojections, the pair of peripheral projections having undercut flangeswhich are mutually facing.
 12. The connecting pole of claim 9, whereinthe connecting pole is formed at least in part by an extrusion press anda rolling tool.
 13. A connecting pole for a rechargeable battery, theconnecting pole comprising: a connecting section, an attachment section,and a labyrinth section; an outer wall surrounding a cavity arranged forintroduction of a pole body, and an inner wall within the cavity, theentire inner wall having a smooth surface; wherein a portion of theouter wall is interrupted a plurality of peripheral projections, atleast one peripheral projection from the plurality of peripheralprojections has an undercut flanged region.
 14. The connecting pole ofclaim 13, wherein the portion of the outer wall which is interrupted bythe plurality of peripheral projections is located on the labyrinthsection.
 15. The connecting pole of claim 13, wherein the plurality ofperipheral projections comprises a pair of peripheral projections, thepair of peripheral projections having undercut flanges which aremutually facing.
 16. The connecting pole of claim 13, wherein theconnecting pole is formed at least in part by an extrusion press and arolling tool.
 17. A connecting pole and housing assembly for arechargeable battery, the assembly comprising: a connecting section, anattachment section, and a labyrinth section; an outer wall surrounding acavity arranged for introduction of a pole body, and an inner wallwithin the cavity, the entire inner wall having a smooth surface;wherein a portion of the outer wall is interrupted a plurality ofperipheral projections, a peripheral projection from the plurality ofperipheral projections having an undercut flanged region; and wherein aconnecting pole is embedded in a material of the rechargeable batteryhousing, the material being provided, within the flanged regions, suchthat a good seal is obtained.
 18. The assembly of claim 17, wherein theportion of the outer wall which is interrupted by the plurality ofperipheral projections is located on the labyrinth section.
 19. Theassembly of claim 17, wherein the plurality of peripheral projectionscomprises a pair of peripheral projections, the pair of peripheralprojections having undercut flanges which are mutually facing.
 20. Theassembly of claim 17, wherein the connecting pole is formed at least inpart by an extrusion press and a rolling tool.
 21. The assembly of claim17, wherein the material of the rechargeable battery housing is aninjection molded material.